1. Field of the Invention
The present invention relates to a manufacturing method for a lead frame applicable to mounting of an integrated circuit or the like.
2. Description of the Related Art
Various methods for mounting an integrated circuit on a printed wiring board have recently been developed. Above all, a mounting technique using a lead frame is widely spread owing to its reliability and low-cost productivity. The mounting technique using the lead frame is also applied to the case of mounting on a mother board a multichip module (MCM) having a plurality of bare IC chips mounted on a substrate. Then, improvement suited for a reduction in cost in manufacturing method for a lead frame has now been desired.
Known as a conventional manufacturing method for a lead frame is a method including the steps of forming a plurality of lead elements by blank etching, for example, and then mechanically deforming the lead elements to form a crank shape of each lead frame.
In the case of applying such a lead frame to a multichip module, the plural lead elements integrally connected together after blank etching are first mounted on the multichip module, and thereafter each lead element is subjected to mechanical deformation (lead forming) and cutting. Accordingly, it is necessary to prepare individual machines for performing the lead forming and the cutting suitable for various forms of the multichip module. As a result, a manufacturing cost for the lead frame is increased.